Polythioureas to inhibit ozone fading of dyed polyamides

ABSTRACT

When from about 0.5 percent to about 5 percent of a polythiourea is coated on nylon fiber an improved dye fastness is achieved compared to untreated dyed nylon fiber when this fiber is exposed to ozone.

United States Patent [19] Wells et al.

[ NOV. 4, 1975 POLYTHIOUREAS TO INHIBIT OZONE FADING OF DYED POLYAMIDES [75] lnventors: Rodney Lee Wells, Chester; Robert Alden Lofquist, Richmond; Stanley David Lazarus, Petersburg, all of Va.

[73] Assignee: Allied Chemical Corporation,

Petersburg, Va.

22 Filed: Feb. 11, 1974 211 App]. No.: 441,595

[52] US. Cl. 8/165; 8/74; 1l7/l38.8 N

[51] Int. Cl. D06P 5/02 [58] Field of Search 8/165, 74; 117/l38.8 N

Primary Examiner-Lewis T. Jacobs Attorney, Agent, or Firm-Richard A. Anderson [57] ABSTRACT 10 Claims, No Drawings POLYTHIOUREAS TO INHIBIT OZONE FADING OF DYEI) POLYAMIDES BACKGROUND OF THE INVENTION The object of this invention is to reduce or prevent the fading of dyed nylon fabrics, such as nylon carpets, caused by ozone.

Ozone is generally present in air at sea level at concentrations of only 1 to parts per hundred million (pphm). Only under conditions of heavy smog, where sunlight acts on a combination of unburned hydrocarbons from gasoline and oxides of nitrogen, does the ozone concentration exceed these concentrations. However, ozone fading occurs even at the low ozone concentrations, if the humidity is high enough (e. g., over 75% RH).

Ozone is a molecular form of oxygen which has three atoms of oxygen instead of the normal two atoms of oxygen per molecule. It is a very powerful oxidizing agent and a strong electrophilic reagent, that is, it searches out and attacks electron pairs such as exist with carbon-carbon double bonds.

Dyes have a multiplicity of double bonds, and perhaps for this reason are very sensitive to ozone.

The dyes in nylon which are most seriously attacked are those which are mobile in the nylon, such as disperse dyes. Cationic dyes are also susceptible. The most sensitive dyes are anthraquinone based, particularly blue dyes having an anthraquinone nucleus, although there is evidence that under high humidity and high ozone concentration almost all dyes are affected by ozone.

High humidity is necessary to cause noticeable ozone fading. Apparently moisture permits the dye to have sufficient mobility to diffuse to the surface of the yarn where the destruction of the dye occurs.

A number of chemicals have been called antiozo-, nants in the literature which protect rubber from ozone. Examples are paraphenylenediamine derivatives, and dihydroquinoline derivatives. In nylon, however, these chemicals seriously discolor the yarn, especially after exposure to light, severely limiting the use of such materials.

Substituted thioureas are disclosed to prevent ozone fading in pending Ser. No. 402,543, filed Oct. 1, 1973 and in Ser. No. 255,628, filed May 26, 1972 now US. Pat. Ser. No. 3,822,996, July 9, 1974. The most pertinent prior art is US. Pat. No. 3,632,363 to Moussalli. This patent discloses the use of a diallyl substituted dithiourea linked by alkyl having 0 to 18 carbon atoms. However, applicants have, in their broadest claim, the proviso that when the polythiourea contains only two thiourea moieties and is allyl substituted, then the thioureas must be joined by a difunctional fatty acid residue moiety of 24 to 108 carbon atoms or a difunctional alkyl substituted cyclic aliphatic hydrocarbon. Applicants have found a much superior effect on resistance to ozone fading than the minor improvement shown in US. Pat. No. 3,632,363.

A method has been found for improving fastness of dyes when exposed to ozone in polycarbonamide fibers. The method consists of coating the fibers with a polythiourea having the formula where .r and y equal 0, 1 or 2, R is a difunctional aliphatic hydrocarbon radical or where Z is H or R R R or R, are independently selected from phenyl or a monofunctional allyl or alkyl radical of 1 to 12 carbon atoms, R and R are (CH (CH or R R are independently selected from H or monofunctional allyl or alkyl radical of 1 to 12 carbon atoms, provided that when x O and R and R are allyl then R must be a difunctional fatty acid residue moiety of 24 to 108 carbon atoms or a difunctional alkyl substituted cyclic aliphatic hydrocarbon, so that from about 0.5 to about 5 percent on weight of the fiber of the compound remains on the fiber after subsequent water treatment to substantially reduce the rate of failure due to exposure of fabric of the dyed fiber due to ozone. The polythioureas of this invention are incorporated in the spin finish, in the over-finish prior to dyeing or sprayed in solutions onto the dyed fiber of nylon 6 or nylon 66. These polythioureas, substantative for polycarbonamide and water-insoluble, remain with the fiber or yarn after subsequent water treatment such as scouring and- /or shampooing and compete with the dye for the ozone, thus decreasing the rate of destruction of the dye. The rate of fading of the dye in nylon fiber, particularly disperse or cationic anthraquinone dyes, is substantially reduced by the incorporation or coating of these polythioureas. This reduction of fading is particularly useful in dyed carpets.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some of the preferred embodiments of this invention are set forth in the following examples. The method of testing for ozone fading is similar to the AATCC Test 129-1968 set forth on page 334/15 of The Journal of American Association of Textile Chemists and Colorisls, July 30, 1969, Volume 1, No. 16, in an article entitled, A New Test Method for Ozone Fading at High Humidity, by Victor S. Salvin.

The method and the means of measuring the loss of. dye consists in dyeing the yarn with a selected dye or dyes, exposing it to ozone at a concentration of 20 parts per hundred million in a test chamber together with a control nylon sample which was dyed an avocado shade. The control sample is examined periodically until the resulting color corresponds to that of the Standard of Fading (one cycle It has been found that one an isopropanol solution of the materials shown below, at 1 gram per 100 milliliters of isopropanol. The control sleeve was sprayed with pure isopropanol. The sleeves were allowed to dry overnight and were then cycle is completed when the internal standard has reweighed and the amount of additive applied was calfaded sufficiently to give a AE of 2.8, compared to the culated. unexposed standard. The sleeves were then heat set by steam treating in an AB is a measure of the change of color between two autoclave at 230F. for 2 cycles of 5 minutes followed samples, asmaller AE beingacloser match, or less fadby 2 cycles at 270F. for 5 minutes and 1 cycle at ing of onesample compared to the second sample. 270F. for 8 minutes.

This color difference, AE was measured with a Hun- The sleeves were dyed to a celery shade in a dye bath terlab Color Differenced Meter. This instrument meacomposed as follows: sures color as seen in average daylight in a manner sim- 0.1 17% Celliton Yellow GA (C.l. Disperse Yellow 3) ilar to the way in which the human eye responds to the C1. 1 1855 stimulus of color. Experimentation has shown that the 0.05% Cibacete Cerise GNB eye can match any color with a combination of three 0.037% Celliton Blue Green BA (C.I. Disperse Blue primary colored lights, and therefore, that any color 7) CI. 62500 can be specified by a three dimensional identification. 2.0% Trisodium phosphate The Color Difference Meter measures the light re- 0.5% Triton X-100, nonionic surfactant by Rohm & flected by a specimen through filters that correspond to 20 Haas C0. the three primary lights. These measurements made The sleeves were held at boil 1 hour. correspond to the way the average human eye responds The dyed sleeves were then exposed to three cycles to light. AB V (AL) (Aa) (Ab) of ozone in an atmosphere of 20 parts per 100,000,000 where of ozone in an atmosphere of l04F., at a relative hu- AL is L L midity of about 90%. A cycle is that exposure which is Ad is a a completed when the internal nylon standard, dyed Av- Ab is b b ocado, has faded sufficiently to give a AE of 2.8. The and L, a, and b are readings on the Hunterlab Color measurement of AB is discussed under the Descrip- Difference Meter. tion of the Preferred Embodiments.

L is a 100 to 0 reading of white to black; The lightfastness was determined by exposure to a indicates redness when positive, gray when Zero, xenon lamp at 145F. for exposures of 20, 40, 60 and and green when negative; 80 hours and visual observation of hours exposure corb indicates yellow when positive, gray when zero and responding to first appearance of a significant break of blue when negative. color of the dyed sleeves. The material applied, the The following are examples of the additives and the amount of coating, the ozone fading and xenon lightmethods of application onto yarns and exposure to fastness are listed as follows:

TABLE 1 Ozone Fading A E Xenon Dye- Lightfastness* Material Applied 7: Added 1 Cycle 2 Cycles 3 Cycles (145F.)

1. None Control 0 4.3 6.8 8.3 2. Bis-allyl thiourea of dimer diamine 1.1 0.7 0.8 1.1 3. Bis-methyl lhiourea of dimer diamine 1.2 0.9 1.6 2.7 60 4. Bis-butyl thiourea of dimer diamine 1.8 1.3 2.0 2.7 40 5. Tetra-ally] thiourea of dimer tetramine 1.1 0.6 1.0 0.8 40 6. Tetra-heptyl thiourea of triethylenetetramine 1.1 0.7 1.1 0.9 40 7. Penta-heptyl thiourea of tetraethylene pentamine 1.1 0.4 0.4 0.9 40 8. Bis-allyl thiourea of menthanediamine 1.2 1.2 2.3 3.5 60 9. Bis-heptyl thiourea of N.N-diethyl 1.7 1.0 1.3 2.2 40

hexanediamine 10. Bis-methyl thiourea of trimethyl hexanediamine 1.4 0.9 1.3 1.6 80 1 1. Bis-allyl thiourea of trimethyl hexanediamine 1.0 0.6 1.0 0.8 40 12. Bisheptyl thiourea of iminobispropylamine 1.1 1 .1 3.4 2.0 40 13. Bis-methyl thiourea of isophorendiamine 1.0 0.5 1.0 1.0 80 14. Bis-allyl thiourea of isophoronediamine 1.0 0.5 0.8 1.1 80

*- Hours to Significant Break Ozone- By dimer diamine is meant H NDNH where D is a 36 EXAMPLE 1 hydrocarbon radical residue of a dimer acid, from which the amine is prepared. By dimer tetramine is Polymer mad from caprolactam, havm g a formic acid meant viscosity of 67, about 66 carboxyls and about 17 amine H N(CH );,HNDNH(CH );,NH ends per million grams of polymer was spun into yarn. 60 where D is as above. Amines may also be prepared The yarn coated with a commercial aqueous finish was from the trimer acids to make the polythioureas of this drawn at a draw ratio of 2.7. The yarn had a Y cross invention. The polythioureas of this invention are presection with a 3.0 modification ratio and each filament pared by reacting alkylisothiocyanates with primary or has a denier of 15. The yarn was chopped into 7 inch secondary diamines, or polyamines such as dimer dilengths, carded and spun into staple yarn having a cotamine, dimer tetramine and NN'-dialkyl diamines or ton count of 2. The yarn was knitted into sleeves.

The sleeves were cut into sections about 15 inches long and weighed. The sleeves were then sprayed with polyamines.

Dimer and trimer acids are viscous liquids produced by the polymerization of unsaturated C fatty acids.

The commercial grades of dimer acid contain Various specified amounts of trimer acid, as well as trace amounts of the monobasic fatty acids from which dimer acid is derived.

Pure dimer acid is a C36 aliphatic, dibasic acid whose structure (see schematic) is essentially that of a long-chain dicarboxylic acid with two alkyl side chains (B and B The structure appears to contain at least one ethylenic bond and another linkage (X) resulting from the polymerization of the two unsaturated fatty acid molecules that form dimer acid. The exact nature of this linkage has not been completely defined: it may be as simple as a single carbon-to-carbon bond, or as complex as a cyclic structure, depending on factors such as the type of unsaturated C fatty acid used, and process conditions such as temperature and catalyst type.

Schematic of Dimer Molecule FIG. 1

Pure trimer acid as a C long-chain tricarboxylic acid whose structure is shown schematically below. The structure of trimer acid is similar to that of dimer acid, but accordingly more complex due to the addi- 6 tional 18 carbon atoms which it contains. Trimer acid has three or more alkyl side chains and two linkages at X in addition to at least one ethylenic bond.

Theoretical Characteristics of Pure Dimer and Trimer 20 Acid ,TABLE II Dimer Acid Trimer Acid Number of carboxyl groups 2 3 25 Number of carbon atoms 36 54 Approx. molecular weight .565 850 Approx. equivalent weight 283 283 STRUCTURE OF COMPOUNDS LISTED IN TABLE I S HnH all H II 1 S il STRUCTURE OF COMPOUNDS LISTED IN TABLE l-continued EXAMPLE 2 FOR CATIONIC DYED SLEEVES The sleeves were cut into sections about 15 inches long and each section was weighed. The sleeves were then sprayed with 1 percent isopropanol solutions of the materials shown below. The sleeves were then allowed to dry overnight, and reweighed. The amount of material applied on the sleeves was based on the difference in weight between the coated and the uncoated sleeves, compared to the control. The sprayed sleeves were heat set by steam treating in an autoclave at 230F. for 2 cycles of 5 minutes followed by two 5 minute cycles of steam treatment at 270F. and one 8 minute cycle at 270F.

The sleeves were dyed to a moss green in a dye bath composed as follows: 0.3% Sevron Yellow SGMF (DuPont) (CJI. Basic Yellow 53) Highpoint Chemical Company, (chemical structure not available) and monosodium and/or disodium phosphate to adjust the pH to 7.0 i 0.2.

The sleeves were then exposed to three cycles of 10 ozone in an atmosphere of about 20 parts per 100,000,000 of ozone at a temperature of 104F., at a relative humidity of 90%. A cycle is that exposure which is completed when the internal nylon standard, dyed Avocado, has faded sufficiently to give a AE of where .r and y are 0, l or 2,. R is a difunctional aliphatic hydrocarbon radical or 15 2.8.The measurement AB is discussed under Description of the Preferred Embodiments.

The additives, the amount applied and the results of R R R or R are independently selected from ozone exposure and xenon lamp (145F.) are listed as phenyl or a monofunctional allyl or alkyl radical of 1 to follows: 2O 12 carbon atoms, R and R are {-Cl-l- ,,-(CH' or Xenon (145F.) AE Dyelightfastness 7: Cycles Hours to Color Additive Added 1 2 3 Break None Control 4.6 16.3 28. 10 Di-heptylthiourea 1.7 1.2 4.0 14.1 of dimer diamine Di-methylthiourea 1.7 1.4 3.9 16.5 of dimer diarnine Di-butylthiourea 1.8 0.6 3 .6 8.2 10 of dimer diamine EXAMPLE 3 Dyed nylon sleeves similar to those of Example 2 were held in 0.5% solutions of the following thioureas for minutes, and then dried in air for 24 hours. The additive pick-up, and the results of exposure to 3 cycles of the ozone fading test given above but with 80 pphm ozone instead of 20 pphm are as follows:

3 Cycles Pick-Up AE 1. Control 21.0 2. Pentaphenylthiourea of 0.5 3.0

tetraethylenepenlamine 3. Diphenylthiourea of 0.7 3.1

hexamethylenediumine 4. Diphenylthiourea of 0.3 6.8

ethylenediamine R R are independently selected from H or monofunctional allyl or alkyl radical of 1 to 12 carbon atoms, provided that when x 0 and R and R are allyl then R must be a difunctional fatty acid residue moiety of 24 to 108 carbon atoms or a difunctional alkyl substituted cyclic aliphatic hydrocarbon,

so that from about 0.5 to about 5 percent on weight of the fiber of the compound remains on said fiber after subsequent water treatment to substantially reduce rate of fading due to exposure to ozone of fabric of said dyed fiber.

2. The method of claim 1 wherein R is a difunctional fatty acid residue moiety of 24 to 108 carbon atoms.

3. The method of claim 2 wherein R R R R are lower allyl or alkyl having 1 to 18 carbon atoms.

4. The method of claim 1 wherein R R R and R are lower alkyl having 1 to 8 carbon atoms.

5. The method of claim 1 wherein said coating is applied prior to dyeing said fiber.

6. The method of claim 1 wherein said coating is applied subsequent to dyeing said fiber.

7. The method of claim 1 wherein said anthraquinone dyes are disperse dyes.

8. The method of claim 1 wherein said anthraquinone dyes are cationic dyes.

9. A polycarbonamide fabric dyed with anthraquinone dyes coated with from about 0.5 to about 5 percent on weight of fabric of a substance consisting essentially of a compound having the formula S R v R 5 R R R or R are independently selected from phenyl l I ll or a monofunctional allyl or alkyl radical of 1 to 12 car- 1 l-T R T bon atoms, R; and R are (CH (CH or C=S C=S l I 5 Til-H l| 1 H CH EH R1 R4 H R R are independently selected from H or monofunctional allyl or alkyl radical of l to 12 carbon atoms, provided that when x equals and R and R are allyl then R must be a difunctional fatty acid f residue moiety of 24 to I08 carbon atoms or a di- R-,-NR"- l functional alkyl substituted cyclic aliphatic hydrocarbon. said compound being substantative to polycarbonamides and whereby said compounds where x and y are 0, l or 2. R is a difunctional alil0 phatic hydrocarbon radical or where Z is H or sure of said fabric to ozone. I l H 10. The fabric of claim 9 wherein said fabric is carpet substantially reduce the rate of fading due to expo-. 

1. A METHOD FOR IMPROVING FASTNESS OF DYES WHEN EXPOSED TO OZONE IN POLYCARBONAMIDE FIBERS DYED WITH ANTHRAQUINONE DYES CONSISTING OF COATING SAID FIBERS WITH A SUBSTANCE CONSISTING ESSENTIALLY OF A COMPOUND HAVING A FORMULA
 2. The method of claim 1 wherein R is a difunctional fatty acid residue moiety of 24 to 108 carbon atoms.
 3. The method of claim 2 wherein R1, R2, R3, R4 are lower allyl or alkyl having 1 to 8 carbon atoms.
 4. The method of claim 1 wherein R1, R2, R3 and R4 are lower alkyl having 1 to 8 carbon atoms.
 5. The method of claim 1 wherein said coating is applied prior to dyeing said fiber.
 6. The method of claim 1 wherein said coating is applied subsequent to dyeing said fiber.
 7. The method of claim 1 wherein said anthraquinone dyes are disperse dyes.
 8. The method of claim 1 wherein said anthraquinone dyes are cationic dyes.
 9. A polycarbonamide fabric dyed with anthraquinone dyes coated with from about 0.5 to about 5 percent on weight of fabric of a substance consisting essentially of a compound having the formula
 10. The fabric of claim 9 wherein said fabric is carpet. 